1. Field of the Invention
The present invention relates to an indwelling needle, and specifically relates to the indwelling needle which stores a needle in a protective cover in a housed state.
2. Description of the Related Art
Presently, puncturing of a patient with a indwelling needle is performed for intravenous drip, dialysis, or the like, on which occasion it is required to prevent a healthcare professional being accidentally punctured with the indwelling needle withdrawn from the patient.
For this reason, there has been known the indwelling needle provided with a needle having a sharp edge formed at the tip thereof, a tubular hub for retaining the proximal end of the needle, and a tubular protective cover slidably provided along the needle (Patent Documents 1-3).
The indwelling needle of Patent Document 1 (Japanese Patent Laid-Open No. 10-85333) is constituted with the hub for retaining the proximal end of a cannula and a retention tube for housing and retaining the hub therein. The cannula is housed in the retention tube by sliding the retention tube.
The indwelling needle of Patent Document 2 (Japanese Patent Laid-Open No. 2002-330945) is constituted with the hub provided at the proximal end of a needle cannula and a safety shield for slidably housing the hub. A spring elastically fitted between the hub and the safety shield extends by operating an actuator from a use state so that the needle cannula is housed in the safety shield.
The indwelling needle of Patent Document 3 (Japanese Patent Laid-Open No. 2003-180829) is constituted with a needle assembly, including the needle cannula and a needle hub, and a body for slidably housing the needle assembly. A puncturing element is housed in the body with elastic force of a spring by operating an operation button when medical treatment is completed.
As described above, according to the indwelling needles of Patent Documents 1-3, a housed state in which the needle is housed in the protective cover is achieved after use, thereby the accident mentioned above is prevented.
However, in the cases of the indwelling needles of the Patent Documents 1-3, the length of the protective cover requires to be set longer than the length that the needle projects from the protective cover, so that the length of a member fixed to a patient in the use state must be set long.
In this case, if used for the patient who is undergoing dialysis therapy, tissue of a punctured site is hardened by being punctured with the needle for many times and forms a knobby swelling. If the member fixed to the patient in the use state is long in length, the indwelling needle touches the swelling when the indwelling needle is fixed to the patient and the angle of the needle inserted in a blood vessel is displaced, which may cause pain to the patient.
In addition, since the Patent Documents 2 and 3, take constitution that the elastic force of the spring retracts the hub relative to the body until the needle is housed in the protective cover, the blood vessel may be damaged by the needle being rapidly withdrawn from the blood vessel and the blood or body fluid adhered to the interior or surface of the needle may splatter.